Sliding sleeve valves are typically shifted down to open ports such as by dropping an object like a ball or plug onto a seat and pressuring up as illustrated in U.S. Pat. Nos. 7,743,647 and 7,108,067. In some designs the same sleeve is shifted once to open ports with the sleeve coming against a shearable travel stop. To close the sleeve another plug is dropped to contact the same sleeve and break the shearable travel stop to move the same sleeve further in the same direction as when the ports opened to again close the ports. This design is illustrated in U.S. Pat. No. 4,246,968. Yet other designs place two sleeves in a concentric alignment and shift the first sleeve 44 to open ports and the second sleeve 46 to close the ports in a housing as illustrated in US Publication 2010/0166665. Other designs combine a ball drop to open the ports with a sleeve and an independent hydraulic system to move the sleeve to close the ports using a complex dual bore structure as in US Publication 2010/0084146. Shifting tools have been designed to move the same sleeve in opposed directions for opening and closing ports as described in US Publication 2010/0108323. Of general interest is a protective sheath that is removable once the sliding sleeve is moved to the open position as described in U.S. Pat. No. 7,870,907 and a sleeve with a collet system for location purposes as described in U.S. Pat. No. 5,479,989.
There are several problems with the above designs. Placing multiple sleeves in a concentric alignment reduces the drift dimension and requires elaborate sealing systems between sleeves. Another problem with concentric sleeves or sleeves that are to be shifted in an opposed direction to close ports is that such motion to close may be made impossible by the nature of the wear adjacent either a port in the sleeve, if used, or the port in the housing through which erosion can take a toll by providing housing or sleeve segments that stick out and snag when trying to shift either a second concentric sleeve or even a single sleeve in an opposed direction to close ports after they have been in service for a period of time.
The present invention provides a low cost option that can operate reliably to open ports and then to close them. Two sleeves are used that operate independently. The opening sleeve can be pushed with an object such as a ball landing on a seat to either align ports in the sleeve and the housing or to move the sleeve clear of a housing port. When it is time to close the housing ports another sleeve that is aligned with the first sleeve but has been in a generally protected position with regard to the erosive stream is then deployed either with a shifting tool or another dropped object to close the housing ports. The closing sleeve is preferably uphole from the opening sleeve but can also be located below the opening sleeve. These and other aspects of the present invention will be more readily understood by those skilled in the art from a review of the detailed description and the associated figure while understanding that the full scope of the invention is to be found in the appended claims.